Supplemental Balance Sheets and Statements of Operations Detail (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Total property and equipment
Property, plant and equipment, gross	$ 1,075,906	$ 1,077,370
Accumulated depreciation	(771,398)	(761,522)
Property, plant and equipment	304,508	315,848
Land and land improvements
Total property and equipment
Useful life	20 years	20 years
Property, plant and equipment, gross	25,824	29,085
Buildings
Total property and equipment
Property, plant and equipment, gross	145,977	136,647
Buildings | Minimum
Total property and equipment
Useful life	20 years	20 years
Buildings | Maximum
Total property and equipment
Useful life	40 years	40 years
Machinery and equipment
Total property and equipment
Useful life	10 years	10 years
Property, plant and equipment, gross	809,884	813,407
Furniture and fixtures
Total property and equipment
Property, plant and equipment, gross	62,072	59,645
Furniture and fixtures | Minimum
Total property and equipment
Useful life	4 years	4 years
Furniture and fixtures | Maximum
Total property and equipment
Useful life	10 years	10 years
Construction in progress
Total property and equipment
Property, plant and equipment, gross	$ 32,149	$ 38,586